Modification of substrate surfaces with polymer coatings

ABSTRACT

A process for forming a polymer film on a substrate through an intermediate organometallic layer is disclosed. A self-assembled monolayer (SAM) containing an initiator for living polymerization such as controlled radical polymerization is formed on the organometallic layer followed by living polymerization such as controlled radical polymerization of a polymerizable monomer component.

FIELD OF THE INVENTION

The present invention relates to modification of substrate surfaces withpolymers prepared by living polymerization such as controlled radicalpolymerization techniques. More particularly, the present inventionrelates to a self-assembled monolayer (SAM) prepared by controlledradical polymerization techniques such as atom transfer radicalpolymerization (ATRP) that are grafted to the substrate surface.

BACKGROUND OF THE INVENTION

Living polymerization such as controlled radical polymerization is ofinterest in polymer chemistry for the preparation of polymers withspecific architectures and functionalities leading to the development ofmaterials with tailored properties. Controlled radical polymerization,particularly Atom Transfer Radical Polymerization, has been conducted toprepare so-called “polymer brushes” on the surfaces of varioussubstrates in which the polymer chains are tethered to the substratesurface. For example, an ATRP initiator is first attached to thesubstrate surface and polymer chains are then grafted from the substratesurface to form a coating layer. These coatings can be of moleculardimensions when the molecule used for attaching the initiator to thesubstrate surface is a SAM. For certain substrates such as glass andplastics, the SAM containing initiator for controlled radicalpolymerization does not adhere well to the substrate surface. This oftenresults in failure of the coating layer.

SUMMARY OF THE INVENTION

The present invention overcomes poor adhesion problems by first applyingto the substrate surface an organometallic layer. The moleculecontaining the living polymerization initiator such as a controlledradical polymerization initiator is then applied to the organometalliclayer to form a SAM adhered to the organometallic layer.

The present invention provides a process for forming a self assembledmonolayer (SAM) of a polymer film on a substrate surface. The SAM isformed by contacting indirectly through an intermediate organometalliclayer, the surface of the substrate with an organophosphorus acid. Theorgano portion of the organophosphorus acid contains an initiator moietyfor living polymerization such as controlled radical polymerization suchas a halide group. The phosphorus acid groups bond to the organometalliclayer with the initiator extending outwardly from the substrate surface.The SAM is then contacted with a monomer component and polymerization isconducted under living polymerization conditions such as controlledradical polymerization conditions, such as by ATRP, to form a thincoating of a polymer on the substrate surface. Living polymerizationsuch as controlled radical polymerization of the monomer componentresults in covalent bonding of the polymer segment to the SAM insuringfor good adhesion and minimal thickness.

In a specific aspect the present invention provides a process forforming a polymer film on a substrate surface comprising:

-   -   (a) contacting the substrate surface through an intermediate        organometallic layer with an organophosphorus acid containing in        a terminal portion a phosphorus acid group, and in a second        terminal portion, an initiator for living polymerization such as        controlled radical polymerization,    -   (b) forming a self-assembled monolayer (SAM) from the compound        with the phosphorus acid group being reactive with the        organometallic layer to bond the organophosphorus acid to the        substrate surface and with the initiator extending outwardly        from the substrate surface,    -   (c) contacting the SAM with a living polymerizable such as a        radically polymerizable monomer component and a living        polymerization catalyst such as a controlled radical        polymerization catalyst, and    -   (d) polymerizing the monomer component with the initiator to        form a polymer layer.

For purposes of the following detailed description, it is to beunderstood that the invention may assume various alternative variationsand step sequences, except where expressly specified to the contrary.Moreover, other than in any operating examples, or where otherwiseindicated, all numbers expressing, for example, quantities ofingredients used in the specification and claims are to be understood asbeing modified in all instances by the term “about”. Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and attached claims are approximations that mayvary depending upon the desired properties to be obtained by the presentinvention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of the invention are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard variation foundin their respective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between (andincluding) the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10.

In this application, the use of the singular includes the plural andplural encompasses singular, unless specifically stated otherwise. Inaddition, in this application, the use of “or” means “and/or” unlessspecifically stated otherwise, even though “and/or” may be explicitlyused in certain instances.

The term “polymer” is also meant to include copolymer and oligomer.

The term “(meth)acryl” refers to both methacryl and acryl compounds suchas methyl methacrylate and methyl acrylate.

The term “acid” is meant to include substances that donate a proton in achemical reaction to a base. The term “acid derivative” is meant toinclude materials that behave similarly to acids such as acid salts, andacid esters, particularly lower alkyl esters containing from 1 to 4carbon atoms.

DETAILED DESCRIPTION

The process according to the present invention utilizes livingpolymerization such as controlled radical polymerization, particularlyatom transfer radical polymerization (ATRP), and the invention will bedescribed in terms of ATRP.

The substrate onto which the films of the present invention can beformed include any substrate that has functionality that will adhere tothe organometallic coating. Examples of such substrates include, but arenot limited to, glass, metal oxide, silicon, quartz and polymericsubstrates. The substrate may take any desired size or shape such as asquare, round, flat chip or a sphere.

The surface of the substrate typically contains reactive functionalgroups such as, for example, hydroxyl groups, thiol groups, metal oxidegroups or mixtures thereof that are capable of bonding such ascovalently bonding with the organometallic coating or layer. The densityof these functional groups is a function of the type of the substratebeing used as well as any steps of preparation that involve exposing thesurface of the substrate to the organometallic coating. Functionalgroups may also be introduced onto the surface of the substrate by beingexposed to chemicals, chemical discharge, plasma treatment, etc. Forexample, a piranha solution can be used to hydroxylate the surface of asilicon substrate. Such substrates, such as metals, have groups, i.e.,metal oxide, available on their surface that are intrinsic to thesubstrate.

The organometallic coating or layer is formed from depositing anorganometallic compound to the substrate surface.

Prior to application of the organometallic compound, the substrate iscleaned such as by a degreasing step particularly if the substrates havebeen in an environment where they have accumulated hydrocarbon films. Adip with an alcoholic solvent such as isopropyl alcohol may be used.

The organometallic compound is preferably derived from a metal ormetalloid, preferably a transition metal, selected from Group III andGroups IIIB, IVB, VB and VIB of the Periodic Table. Transition metalsare preferred, such as those selected from Groups IIIB, IVB, VB and VIBof the Periodic Table. Examples are tantalum, titanium, zirconium,lanthanum, hafnium and tungsten. The organo portion of theorganometallic compound is selected from those groups that are reactivewith functional groups, such as acid groups (or their derivatives) ofthe organophosphorus acid. Also, as will be described later, the organogroup of the organometallic compound is believed to be reactive withgroups on the substrate surfaces being treated such as oxide andhydroxyl groups. Examples of suitable organo groups of theorganometallic compound are alkoxide groups containing from 1 to 18,preferably 2 to 4 carbon atoms, such as ethoxide, propoxide,isopropoxide, butoxide, isobutoxide, tert-butoxide and ethylhexyloxide.Mixed groups such as alkoxide, acetyl acetonate and chloride groups canbe used.

The organometallic compounds can be in the form of simple alkoxylates orpolymeric forms of the alkoxylate, and various chelates and complexes.For example, in the case of titanium and zirconium, the organometalliccompound can include:

a. alkoxylates of titanium and zirconium having the general formulaM(OR)₄, wherein M is selected from Ti and Zr and R is C₁₋₁₈ alkyl,

b. polymeric alkyl titanates and zirconates obtainable by condensationof the alkoxylates of (a), i.e., partially hydrolyzed alkoxylates of thegeneral formula RO[-M(OR)₂O—]_(x-1)R, wherein M and R are as above and xis a positive integer,

c. titanium chelates, derived from ortho titanic acid and polyfunctionalalcohols containing one or more additional hydroxyl, halo, keto,carboxyl or amino groups capable of donating electrons to titanium.Examples of these chelates are those having the general formulaTi(O)_(a)(OH)_(b)(OR′)_(c)(XY)_(d)wherein a=4−b−c−d; b=4−a−c−d; c=4−a−b−d; d=4−a−b−c; R′ is H, R as aboveor X—Y, wherein X is an electron donating group such as oxygen ornitrogen and Y is an aliphatic radical having a two or three carbon atomchain such as

-   -   i. —CH₂CH₂—, e.g., of ethanolamine, diethanolamine and        triethanolamine,

-   -   ii. e.g., of lactic acid,

-   -   iii. e.g., of acetylacetone enol form, and

-   -   iv. e.g., as in 1,3-octyleneglycol,

d. titanium acylates having the general formula Ti(OCOR)_(4-n)(OR)_(n)wherein R is C₁₋₁₈ alkyl as above and n is an integer of from 1 to 3,and polymeric forms thereof,

e. mixtures thereof.

The organometallic compound is usually dissolved or dispersed in adiluent. Examples of suitable diluents are alcohols such as methanol,ethanol and propanol, aliphatic hydrocarbons, such as hexane, isooctaneand decane, ethers, for example, tetrahydrofuran and dialkyl ethers suchas diethyl ether. Alternatively, the organometallic compound can beapplied by vapor deposition techniques.

Also, adjuvant materials may be present with the organometallic compoundand the diluent (organometallic compositions). Examples includestabilizers such as sterically hindered alcohols, surfactants andanti-static agents. The adjuvants if present are present in amounts ofup to 30 percent by weight based on the non-volatile content of thecomposition.

The concentration of the organometallic compound in the composition isnot particularly critical but is usually at least 0.01 millimolar,typically from 0.01 to 100 millimolar, and more typically from 0.1 to 50millimolar.

The organometallic treating composition can be obtained by mixing all ofthe components at the same time or by combining the ingredients inseveral steps. Since in some cases, the organometallic compound isreactive with moisture, care should be taken that moisture is notintroduced with the diluent or adjuvant materials and that mixing isconducted in a substantially anhydrous atmosphere.

The organometallic composition can be applied to the substrate surfaceby conventional means such as immersion coating such as dipping,rolling, spraying or wiping to form a film. The diluent is permitted toevaporate. This can be accomplished by heating to 50-200° C. or bysimple exposure to ambient temperature, that is, from 20-25° C. It isbelieved that the resulting film is in the form of a polymeric metaloxide in multilayer form with unreacted alkoxide and hydroxyl groups.This is accomplished by depositing the film under conditions resultingin hydrolysis and self-condensation of the alkoxide. These reactionsresult in a polymeric coating being formed that provides cohesivestrength to the film. The conditions necessary for these reactions tooccur is to deposit the film in the presence of water, such as amoisture-containing atmosphere, however, these reactions can beperformed in solution by the careful addition of water. The resultingfilm has some unreacted alkoxide groups and/or hydroxyl groups forsubsequent reaction and covalent bonding with co-reactive functionalgroups on the substrate surface and with the organophosphorus acidgroups of the SAM overlayer. However, for readily co-reactive groups,ambient temperatures, that is, 20° C., may be sufficient. Although notintending to be bound by any theory, it is believed the polymeric metaloxide is of the structure:[M(O)_(x)(OH)_(y)(OR)_(z)]_(n)where M is the metal of the invention; R is an alkyl group containingfrom 1 to 30 carbon atoms; x+y+z=V, the valence of M; x is at least 1; yis at least 1; z is at least 1; x=V−y−z; y=V−x−z; z=V−x−y; n is greaterthan 2, such as 2 to 1000. Optionally, the organometallic film may alsocontain chloride ligands.

The resulting film typically has a thickness of 0.5 to 100 nanometers.For other applications, thicker films can be used. When theorganometallic compound is used neat and applied by chemical vapordeposition techniques in the absence of moisture, a thin metal alkoxidefilm is believed to form. Polymerization, if any occurs, is minimizedand the film may be in monolayer configuration. When the organometalliccompound is subjected to hydrolysis and self-condensation conditions asmentioned above, thicker films are formed.

In accordance with the process of the present invention, theorganometallic layer is first contacted with initiator molecules to forma SAM of an initiator. The initiator-coated substrate is then contactedwith a monomer component and an ATRP catalyst and polymerized under ATRPconditions to form a polymer layer or film.

The organophosphorus acid that is used to form the SAM can be anorganophosphoric acid, an organophosphonic acid or an organophosphinicacid. Typical organophosphorus acids are those of the structure:

where R and R¹ are independently organic radicals that are aliphatic,aromatic or mixed aliphatic/aromatic; R and/or R¹ is substituted in theterminal position with an initiator for ATRP, typically a halide moietysuch as bromide or chloride.

Specific examples of organophosphorus acids are those of the structure:

where n is an integer of 1 to 5; R₁ is an alkyl group of 1 to 20 carbonatoms; R₂ is hydrogen or alkyl of 1 to 20 carbon atoms and X is bromideor chloride. A specific example of such a compound is11-(2-bromo-2-methylpropionyloxy)undecyl-1-phosphonic acid.

For application to the organometallic layer, the organophosphorus acidis dissolved in a liquid diluent, however it can also be applied viavacuum evaporation. The concentration is typically dilute, for example,no greater than 10 percent on a weight/volume basis, and preferably iswithin the range of 0.01 to 1.0 percent. The percentages are based ontotal weight or volume of the solution.

Examples of diluents are water or hydrocarbons such as hexane, isooctaneand toluene; ketones such as methyl ethyl ketone; alcohols such asmethanol, ethanol and isopropanol; and ethers such as tetrahydrofuran.

The solution of the organophosphorus acid can be applied to theorganometallic layer by dipping, rolling, spraying, printing, stamping,or wiping. After application of the organophosphorus acid, the diluentis permitted to evaporate, with or without wiping during evaporation,preferably at ambient temperature, or optionally by the application ofheat.

The resultant layer is typically thin, having a thickness of about 100nanometers or less, such as 0.5 to 100 nanometers. It is preferable (butnot required) that the layer is rinsed with fresh solvent, such asacetone or ethanol before being exposed to the polymerization mixture,as excess initiator will dissolve into the layer and cause undesirablebulk polymer formation in solution.

The organophosphorus acid forms a SAM on the surface of theorganometallic layer. The self-assembled layer is formed by theadsorption and spontaneous organization of the organophosphorus acid onthe organometallic layer. The organophosphorus acids are amphiphilicmolecules that have two functional groups. The first functional group,i.e., the head functional group, is an acid group that adsorbs on theorganometallic layer and covalently bonds to the organometallic layerthrough reaction with cofunctional groups such as alkoxide and/orhydroxyl groups. The second functional group, i.e., the tail, the organogroups containing the initiator groups in the terminal position extendoutwardly from the surface of the substrate. It is believed that in thisconfiguration the monolayer, although very thin, is very effective inpromoting adhesion to the substrate.

Although not intending to be bound by any theory, it is believed thefunctional groups such as the acid of the organophosphorus compoundcovalently bond with the hydroxyl or alkoxide group of theorganometallic coating, resulting in a durable film. It is believed thatthe organophosphorus acids form a self-assembled layer that may be atleast in part a monolayer on the surface of the substrate as generallydescribed above.

The SAM as described above is contacted with a radically polymerizablemonomer component that also contains an ATRP catalyst, at least oneligand and a reducing agent, all dissolved in a suitable diluent.Examples of monomers are carbobetaines, sulfobetaines and fluorocarbonmonomers. These carbobetaine and sulfobetaine monomers typically havethe following structure:

where R₁ is hydrogen or methyl; A is oxygen or —NH—; R₂ is ethylene orpropylene; B is N or P; R₃ and R₄ are alkyl typically containing from 1to 4 carbon atoms; n is an integer of 1 to 4; and X⁻ is SO₃ ⁻ or CO₂ ⁻.Examples of such monomers are [2-(methacryloyloxy)ethyl]dimethyl-(3sulfopropyl)ammonium hydroxide and [2-(methacryloyloxy)ethyl]dimethyl-(2carboxyethyl)ammonium hydroxide.

Examples of fluorocarbon monomers are those of the following structure:CH₂═CR—C(O)O—(CH₂)_(n)—R_(f)  (I)wherein R is hydrogen or methyl, n is an integer in the range of from 0to 20; and R_(f) is a fluoroalkyl group having in the range of from 1 to20 carbon atoms. In one embodiment, R is methyl, n is 2 and R_(f) isC₆F₁₃, which is commercially available as CAPSTONE™ 62-MA from DuPont,Wilmington, Del. Examples of suitable fluorine-containing monomersaccording to formula (I) can include, for example, perfluoromethyl ethyl(meth)acrylate, perfluoroethyl ethyl (meth)acrylate, perfluorobutylethyl (meth)acrylate, perfluoropentyl ethyl (meth)acrylate,perfluorohexyl ethyl (meth)acrylate, perfluorooctyl ethyl(meth)acrylate, perfluorodecyl ethyl (meth)acrylate, perfluorolaurylethyl (meth)acrylate, perfluorostearyl ethyl (meth)acrylate orcombinations thereof.

Besides the betaine-containing and fluorocarbon monomers, the radicallypolymerizable component may contain a different radically polymerizablemonomer or mixture of monomers. Examples include olefins such asethylene and propylene; (meth)acrylol monomers such as (meth)acrylicacid and esters thereof such as methyl (meth)acrylate and ethyl(meth)acrylate; substituted esters thereof such as hydroxypropyl(meth)acrylate and hydroxyethyl (meth)acrylate and vinyl aromaticcompounds such as styrene and vinyl toluene.

When present, the betaine-containing monomer or the fluorocarbon monomeris typically present in the radically polymerizable monomer component inamounts of 10 to 100, usually 50 to 100 percent by weight; thepercentages by weight being based on total monomer weight. The radicallypolymerizable monomer component is used in combination with an ATRPpolymerization catalyst, typically a transition metal compound, whichparticipates in a reversible redox cycle with the initiator; and aligand, which coordinates with the transition metal compound. The ATRPprocess is described in further detail in International PatentPublication No. WO 98/40415 and U.S. Pat. Nos. 5,807,937, 5,763,548 and5,789,487.

Catalysts that may be used in the ATRP preparation include anytransition metal compound. It is preferred that the transition metalcompound not form direct carbon-metal bonds with the polymer chain.Transition metal catalysts useful in the present invention may berepresented by the following general formula:M^(n+)X_(n)wherein M is the transition metal, n is the formal charge on thetransition metal having a value of from 0 to 7, and X is a counterion orcovalently bonded component. Examples of the transition metal M include,but are not limited to, Cu, Fe, Au, Ag, Hg, Pd, Pt, Co, Mn, Ru, Mo, Nband Zn. Examples of X include, but are not limited to, halide, hydroxy,oxygen, C₁-C₆ alkoxy, cyano, cyanato, thiocyanato and azido. A preferredtransition metal is Cu(I) and X is preferably halide, e.g., chloride.Accordingly, a preferred class of transition metal catalyst is thecopper halides, e.g., Cu(I)Cl. It is also preferred that the transitionmetal catalyst contain a small amount, e.g., 1 mole percent, of a redoxconjugate, for example, Cu(II)Cl₂, when Cu(I)Cl is used. Additionalcatalyst useful in preparing the pigment dispersant are described inU.S. Pat. No. 5,807,937 at column 18, lines 29 through 56. Redoxconjugates are described in further detail in U.S. Pat. No. 5,807,937 atcolumn 11, line 1 through column 13, line 38.

Ligands that may be used in the ATRP preparation of the pigmentdispersant include, but are not limited to, compounds having one or morenitrogen, oxygen, phosphorus and/or sulfur atoms, which can coordinateto the transition metal catalyst compound, e.g., through sigma and/or pibonds. Classes of useful ligands include, but are not limited to,unsubstituted and substituted pyridines and bipyridines; porphyrins;cryptands; crown ethers; e.g., 18-crown-6; polyamines, e.g.,ethylenediamine; glycols, e.g., alkylene glycols, such as ethyleneglycol; carbon monoxide; and coordinating monomers, e.g., styrene,acrylonitrile and hydroxyalkyl(meth)acrylates. As used herein and in theclaims, the term “(meth)acrylate” and similar terms refer to acrylates,methacrylates and mixtures of acrylates and methacrylates. A preferredclass of ligands are the substituted bipyridines, e.g.,4,4′-dialkyl-bipyridyls. Additional ligands that may be used inpreparing pigment dispersant are described in U.S. Pat. No. 5,807,937 atcolumn 18, line 57 through column 21, line 43.

The reducing agent may be any reducing agent capable of reducing thetransition metal catalyst from a higher oxidation state to a loweroxidation state, thereby reforming the catalyst activator state. Suchreducing agents include, but are not limited to, SO₂, sulfites,bisulfites, thiosulfites, mercaptans, hydroxylamines, hydrazine (N₂H₄),phenylhydrazine (Ph-NHNH₂), hydrazones, hydroquinone, foodpreservatives, flavonoids, beta carotene, vitamin A, α-tocopherols,vitamin E, propyl gallate, octyl gallate, BHA, BHT, propionic acids,ascorbic acid, sorbates, reducing sugars, sugars comprising an aldehydegroup glucose, lactose, fructose, dextrose, potassium tartrate,nitriles, nitrites, dextrin, aldehydes, glycine, and transition metalsalts.

The above-mentioned ingredients are typically dissolved in a diluentsuch as an organic solvent, for example, acetone or methanol. Alsosolvents such as those containing oligo ethylene oxide and propyleneoxide groups, such as diethylene glycol, diethylene glycol monomethylether and tripropylene glycol monomethyl ether may be used. Suchsolvents often boost the activity of the catalyst. The concentration ofthe radically polymerizable monomer is typically from 5 to 70 percent byweight based on total weight of solution. The molar ratio of catalyst tomonomer ranges from 1:5 to 1:500, such as 1:20 to 1:100; the molar ratioof ligand to catalyst ranges from 1:2 to 1:100, such as 1:2 to 1:5. Themolar ratio of reducing agent to catalyst is from 1:0.1 to 10 such as1:0.5 to 2.

The solution of the radically polymerizable monomer component can beapplied to the initiator-coated substrate by conventional means such asdipping, rolling, spraying, printing, stamping or wiping. The formationof the ATRP film or coating can occur at temperatures in the range of25-150° C. and at pressures of 1-100 atmospheres, usually at ambienttemperature and pressure. The time for conducting the ATRP can varydepending on the thickness of the film desired. Films of less than 1000nanometers, usually from 100-500 nanometers, are useful for mostapplications. The thickness of the film can be monitored by QuartzCrystal Microgravometric (QCM) measurement and the time for the ATRP istypically from 30 to 600 minutes. After ATRP, the coated substrate isremoved from any remaining solution by rinsing with a polar solvent anddrying the coated substrate.

When the surface of the initiator-coated substrate is exposed to thesolution of the radically polymerizable monomer component and subjectedto ATRP conditions, the monomers contained therein form covalent bondswith each other and with the initiator groups that are bonded to theorganometallic layer. As mentioned above, the resultant coating or filmis relatively thin with strong adhesion to the organometallic layer. Theresulting polymer has a low polydispersity index because chain transferreactions are minimized. Lower polydispersity indices enable themolecular weight of the polymer to be controlled and optimized for theparticular application intended.

EXAMPLES Example 1

The following example shows the preparation of a coating prepared viaATRP of sulfobetaine monomer on a SAM of an initiator-coatedborosilicate glass substrate. All parts are by weight unless otherwiseindicated.

The materials used in the Example were as follows:

Organometallic solution: 0.025% by weight of tantalum ethoxide inisopropanol and 0.0025% by weight anhydrous hydrochloric acid inisopropanol.

Organophosphorus acid: 1 micromole of 11-(2-bromoisobutyrol) undecylphosphonic acid in toluene.

Sulfobetaine monomer: [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide.

Catalyst: Copper (I) Bromide.

Ligand: N,N,N,N,N pentamethyldiethylene triamine (PMDETA).

Reducing agent: sodium ascorbate.

Borosilicate glass slides (2.5×7.5 cm) were cleaned by immersion in aheated solution (60-70° C.) of 1% Alconox powdered precision cleaner indistilled water, rinsed under running water then dried with cleancompressed air.

After cleaning, the substrate was dipped in the organometallic solutionfor 10 seconds and slowly removed (about 4 cm/minute) from the solutionand allowed to air dry vertically. The panels were then heated at 60° C.for 5 minutes. The panels were then dipped in the organophosphorus acidsolution for 5 minutes, removed and immediately rinsed with toluene. Thecoated panels were blown dry and then heated at 60° C. for 5 minutes.

A polymerization solution was prepared by first preparing a 1 molarsolution of the sulfobetaine monomer in 20 mL of water. The solution wasdegassed with a nitrogen needle for 15 minutes. 40 mg of catalyst wasadded to 1 mole/liter of the sulfobetaine monomer solution followed bythe addition of 0.26 milliliters of PMDETA and 10 mg of the reducingagent.

The coated panels were placed in a sealed glass polymerization chamber,and the chamber purged with a nitrogen-free gas. The polymer solutionwas then continuously injected via a syringe pump into the chamber(excess flowing into a waste container) at ambient conditions oftemperature and pressure and the thickness of the forming film wasmonitored by QCM. The reaction was terminated by stopping injection ofthe polymerization solution when the thickness of the film was about 50nanometers. The time of film formation was 240 minutes.

Example 2

The following example shows the preparation of a coating prepared viaATRP of a fluorocarbon monomer on a SAM of an initiator-coatedborosilicate glass substrate. All parts are by weight unless otherwiseindicated.

The materials used in the Example were as follows:

Organometallic solution: 0.025% by weight of tantalum ethoxide inisopropanol and 0.0025% by weight anhydrous hydrochloric acid inisopropanol.

Organophosphorus acid: 1 micromole of 11-(2-bromoisobutyrol) undecylphosphonic acid in toluene.

Fluorocarbon monomer: CAPSTONE 62-MA (a mixture of C₄-C₈ perfluoroalkylmethacrylate monomers sold by DuPont®).

Catalyst: Copper (I) Bromide.

Ligand: N,N,N,N,N pentamethyldiethylene triamine (PMDETA).

Reducing agent: Tin (II) ethylhexanoate.

Borosilicate glass slides (2.5×7.5 cm) were cleaned by immersion in aheated solution (60-70° C.) of 1% Alconox powdered precision cleaner indistilled water, rinsed under running water then dried with cleancompressed air.

After cleaning, the substrate was dipped in the organometallic solutionfor 10 seconds and slowly removed (about 4 cm/minute) from the solutionand allowed to air dry vertically. The panels were then heated at 60° C.for 5 minutes. The panels were then dipped in the organophosphorus acidsolution for 5 minutes, removed and immediately rinsed with toluene. Thecoated panels were blown dry and then heated at 60° C. for 5 minutes.

A polymerization solution was prepared by first preparing a 40% byvolume solution of the fluorocarbon monomer in a 70/30 mixture ofacetone and triethylene glycol monomethyl ether. The solution wasdegassed with a nitrogen needle for 15 minutes. 43 mg of catalyst wasadded to 20 milliliters of the fluorocarbon monomer solution followed bythe addition of 0.15 milliliters of PMDETA and 150 mg of the reducingagent.

The coated panels were placed in a sealed glass polymerization chamber,and the chamber purged with a nitrogen-free gas. The polymer solutionwas then continuously injected via a syringe pump into the chamber(excess flowing into a waste container) at ambient conditions oftemperature and pressure and the thickness of the forming film wasmonitored by QCM. The reaction was terminated by stopping injection ofthe polymerization solution when the thickness of the film was about 150nanometers. The time of film formation was 300 minutes.

The invention is now set forth in the following claims.

The invention claimed is:
 1. A process for forming a polymer film on asubstrate surface comprising: (a) contacting the substrate surfacethrough an intermediate organometallic layer with an organophosphorusacid comprising a phosphorous acid group and an organo group having aterminal portion, wherein said terminal portion of said organo group issubstituted with an initiator for controlled radical polymerization, (b)forming a self-assembled monolayer (SAM) from the organophosphorus acidwith the phosphorus acid group being reactive with the organometalliclayer to bond the organophosphorus acid to the substrate surface andwith the initiator extending outwardly from the substrate surface, (c)contacting the SAM with a radically polymerizable monomer component anda controlled radical polymerization catalyst, and (d) polymerizing themonomer component with the initiator to form a polymer layer.
 2. Theprocess of claim 1 wherein the substrate has functional groups on itssurface selected from the group consisting of oxide and hydroxyl.
 3. Theprocess of claim 1 in which the substrate is selected from the groupconsisting of metals, glass and polymers.
 4. The process of claim 1 inwhich the organometallic layer is a polymeric metal oxide.
 5. Theprocess of claim 4 in which the polymeric metal oxide contains alkoxideand hydroxyl ligands.
 6. The process of claim 4 in which the polymericmetal oxide contains chloride ligands.
 7. The process of claim 1 inwhich the metal of the organometallic layer is selected from tantalum,titanium, zirconium, lanthanum, hafnium, niobium and tungsten.
 8. Theprocess of claim 1 in which the organophosphorus acid is a phosphonicacid containing an organo group in which the organo group contains in aterminal position said initiator for controlled radical polymerization.9. The process of claim 8 in which the initiator is a halide group. 10.The process of claim 1 in which the organophosphorus acid is selectedfrom the group consisting of organophosphoric acids, organophosphonicacids and organophosphinic acids.
 11. The process of claim 1 in whichthe organophosphorus acid is a phosphonic acid containing an organogroup in which the organo group contains a terminal halide group. 12.The process of claim 1 in which the organophosphorus acid is of thestructure:

where R and R¹ are independently organic radicals that are aliphatic,aromatic or mixed aliphatic/aromatic; and R and/or R¹ is substituted ina terminal position with said initiator for controlled radicalpolymerization.
 13. The process of claim 12 in which the initiator is ahalide.
 14. The process of claim 13 in which the organophosphorus acidis of the structure:

where n is an integer of 1 to 5; R₁ is an alkyl group of 1 to 20 carbonatoms; R₂ is hydrogen or alkyl of 1 to 20 carbon atoms and X is bromideor chloride.
 15. The process of claim 1 wherein the organophosphorusacid is 11-(2-bromo-2-methylpropionyloxy)-undecyl-1-phosphonic acid. 16.The process of claim 1 in which the radically polymerizable monomercomponent is an ethylenically unsaturated monomer selected from thegroup consisting of olefins, (meth)acryl monomers, and vinyl aromaticcompounds.
 17. The process of claim 1 in which the polymerization step(d) is atom transfer radical polymerization.